Saw chain with alternating long and short pitch



Nov. 17, 1959 H. I. HAZZARD SAW CHAIN WITH ALTERNATING LONG AND SHORT PITCH Filed July 12, 1957 HARRYI- HAZZARD INVENTOR.

A Al /awn All United States Patent SAW CHAIN WITH ALTERNATING LONG AND SHORT PITCH Harry I. Hazzard, Los Angeles, Calif., assignor to McC ulloch Corporation, Los Angeles, Calif., a corporation of Wisconsin Application July 12, 1957, Serial No. 671,490

4 Claims. (Cl. 143135) This invention relates to saw chains of the character employed for the cutting of wood. These saw chains consist of links connected by pintles, some of the links having cutting elements projecting therefrom, so that as the saw chain is caused to travel along a supporting member, such as a saw bar, the cutters will cut a kerf in the object being sawed.

It is an object of the invention to generally improve these saw chains so that they will give better performance and will have longer useful life.

It is an object of the invention to provide a saw chain consisting of long links and short links connected by hinge means disposed on transverse axes, the long links having their hinge axes spaced apart at a greater distance than the spacing of the hinge axes of the short links. In the ordinary practice of the invention, the hinge means consist of pintles which extend through pintle openings disposed near the ends of the links. The pintle openings of the long links are spaced apart a greater distance than the pintle openings of the short links, thereby providing definite advantages and improvements in the saw chain. Among these advantages are the following: reduced rearback of the cutters because they are mounted on the long links, use of larger pintles and more metal around the pintles giving greater strength, lower polar moment of inertia, and improved tooth form in the sprockets over which the chain is run.

An important object of the invention is to provide a long tooth body, permitting greater cutter length and many additional sharpenings and, therefore, longer life.

Further objects and advantages of the invention may be brought out in the following 'part of the specification where small details of construction have been described for the purpose of disclosure without intending, however, to limit the scope of the invention which is defined by the appended claims.

Referring to the accompanying drawings which are for illustrative purposes only:

Fig. 1 is a plan view of a preferred embodiment of the invention;

Fig. 2 is a side view of the chain shown in Fig. 1;

Fig. '3 is an enlarged sectional view taken as indicated by the line 33 of Fig. 2;

Fig. 4 is a plan view of a chain of alternative form; and

Fig. 5 is a face view of the chain shown in Fig. 4.

Referring to the form of the invention shown in Figs. 1, 2 and 3, the chain includes long links and short links 11 connected by pintles 12. The long links 10 are side links and the short links 11 are center links having sprocket engaging bodies 13 projecting downwardly therefrom. The terms long and short refer to the spacing of the axes of the pintle openings 14 and 15 in the respective par-ts 10 and 11. The openings 14 of the long links 10 are spaced so that the axes thereof are separated by a distance D, and the openings 15 of the short links are disposed on axes separated by a distance d which is less than the distance D.

, 2,913,023 Patented Nov. 17, 1959 Selected long links 10 specifically designated by the numerals 10c have cutters 16 projecting therefrom, each of these cutters 16 having a plate or shank portion- 17 which extends outwardly from the body of the link 10 and a chisel or toe portion 18 extending transversely from the outer end of the shank portion 17. The cutter 16 is sharpened at its forward end to provide a cutting edge 19. On each selected long link, which may be referred to as a cutter link 10c, a gauge 20 is disposed ahead of the cutter 16.

The spacing of the cutters 16 along the length of the chain is determined by conditions under which the chain is to be used. For example, if the chain is to be used for cutting extremely soft wood so that large chips are formed, then the cutters must be spaced further apart so as to provide sufiicient chip carrying space between consecutive cutters. Also, if the chain is to be operated at high speed, as in chain saw devices having direct drives so that the chain driving sprocket revolves at the same speed as the engine crankshaft, it may be desirable to space the cutters further apart.

The chain shown in Figs. 1 and 2 may be regarded as having its links arranged in units, each unit consisting center link 11. The pintle 12 has stems 22 which extend i outwardly from the opposite faces of the body portion 21 through the openings 14, the outer ends of the stems 22 being riveted over so as to clamp the respective side links 10 firmly against the side faces of the body portion 21.

In the form of the invention shown in Figs. 4 and 5, I provide long links 25 and short links 26 connected by pintles 27 in alternating order. In this form of the invention the long links 25 are center links and the short links 26 are side links. The long links are so called because their pintle openings are arranged with their axes spaced apart a distance D which is greater than the distance d at which the axes of the openings of the short links 26 are spaced apart. From selected long links 250, which may be referred to as the cutter links of the chain, cutters 28 extend outwardly, these cutters 28 each comprising a shank portion 29 and a toe portion 30. The cutters 28 are of essentially the same form as the cutters 16 shown in Figs. l-3, but they are formed and extend outwardly from center links 25C instead of from side links .of the chain. The center links 25 have sprocket-engaging bodies 31 projecting inwardly therefrom.

In the form of the chain, shown in Figs. 4 and 5, alternate long links 25 are selected as cutter links 250 so that between adjacent cutter links 250 there are two pairs of side links 26 and a single center link 25, specifically indicated by the numeral 25 which merely serves as a spacer link. It will be understood that the cutter links 250 may be arranged at suitable distances apart in accordance with the conditions of operation for which the chain has been designed.

I claim:

1. In a saw chain: long side links and short center links alternately connected by hinge means disposed on transverse hinge axes, the hinge axes of said long links being spaced apart a greater distance than the hinge axes of said short-links, and cutter elements extending from selected said long links for cutting a kerf in the material to be sawed, said cutter elements comprising shank portions which extend outwardly from and for a substantial portion of the length of said selected long links and toe providing hinges between alternately connected long links and short links, and cutter elements extending from selected said long links for cutting a kerf in the material to be sawed, said cutter elements comprising shank portions which extend outwardly from and for a substantial portion of the length of said selected long links and toe portions which extend from the outer edge of said shank portions.

3. In a saw chain: long side links and short center links alternately connected by hinge means disposed on transverse hinge axes, the hinge axes of said long links being spaced apart a greater distance than the hinge axes of said short links; cutter elements extending from selected long side links positioned on opposite sides of the chain for cutting a kerf in the material to be sawed, said "cutter elements comprising shank portions which extend outwardly from and for a substantial portion of the length of said selected long side links and toe portions which extend from the outeredge of said shank portions toward the longitudinal center plane of said chain, the

successive toe portions along said chain extending in opposite transverse directions relative to said center plane; and projections carried by said short center links for engaging a driving sprocket, said projections extending inwardly from said short center links.

4. In a saw chain: long side links and short center links alternately connected by hinge means disposed on transverse hinge axes, the hinge axes of said long side links being spaced apart a greater distance than the hinge axes of said short center links; cutter elements extending from selected long side links positioned on opposite sides of the chain for cutting a kerf in the material to be sawed, said cutter elements comprising shank portions which extend outwardly from and for a substantial portion of the length of said selected long links and toe portions which extend from the outer edge of said shank portions, each of the successive toe portions along said chain extending in opposite transverse directions toward a long side link on the opposite side of said chain, a depth gauge on each said selected long side links disposed forwardly of the cutter element on such links; and projections carried by said short center links extending inwardly therefrom for engaging a driving sprocket.

References Cited in the file of this patent UNITED STATES PATENTS Re. 24,129 Hassler Mar. 13, 1956 2,558,678 Garrett June 26, 1951 2,622,636 Cox Dec. 23, 1952 FOREIGN PATENTS 518,137 Canada Nov. 8, 1955 885,478 Germany Aug. 6, 1953 1,102,721 France May 11, 1955 

